Sen. Orrin Hatch would have a tough road to re-election in a three-way Utah Republican primary, a new poll found.

The Utah Policy/Exoro Group poll, conducted by locally based Dan Jones & Associates Inc., found Hatch in third place in a hypothetical GOP primary matchup with former Gov. Jon Huntsman and Rep. Jason Chaffetz.

With the state’s open primary system, the poll was conducted of 509 registered voters, including Republicans, Democrats and independents. Huntsman finished well ahead with 48 percent, followed by

Chaffetz with 23 percent and Hatch with 21 percent.

Among only Republicans, Huntsman took 40 percent, Chaffetz 30 percent and Hatch 26 percent.

However, it’s possible the Republican nominee will be decided in the state party convention, where only locally elected delegates are eligible to vote — something Chaffetz noted to the Deseret News. “The only poll that will matter is of Utah state delegates in May of 2012,” he said.

Huntsman, the ambassador to China, has not made any indication that he is considering a Senate bid, though he hinted about a future run for office in an interview with Newsweek. Chaffetz has said he’s thinking about challenging Hatch.

Former Sen. Bob Bennett’s re-election campaign ended at the May 2010 convention, when now-Sen. Mike Lee and Tim Bridgewater finished ahead of him.

The top two finishers at the convention advance to the primary unless one candidate receives 60 percent of the convention vote. Bennett became the first Senator from the state in seven decades to lose his party’s nomination.